The present invention relates to a method for interfacing between a key-phone system and a subset key-phone, and more particularly to a method for increasing data interfacing speed between a key-phone system and a subset key-phone.
In general, a central processing unit (CPU) of a key-phone system assigns 10 ms to each key-phone subscriber to execute a given service successfully for all events generated from the key-phone. In a conventional key-phone system, when a data interfacing process between a central processing unit and a key-phone subscriber is executed, every universal async receiver and transmitter (hereinafter referred to as UART) covers eight subscribers, so that a response time for processing the corresponding events with the central processing unit according to the events generated from the key-phone system is very slow, and when the key-phone employs an liquid crystal display (LCD) for displaying a state initiated by the subscriber, the processing speed is so slow that it is displayed on the LCD means very late. In addition to these disadvantages, the prior art has another disadvantage that when a user inputs the key with a high speed, a response time for late key input key is too slow to take proper action.